In the world of philately a frequent problem is the identification of the perforations on a stamp, the number of perforation along the two centimeters at the sides, sometimes with a difference between the vertical and the horizontal sides (as they can be different); this operation usually made over an important number of stamps is carried out by means of a number of rulers graduated to such purpose, a perforation gauge, that compares the horizontal (and vertical) sides with the most similar scale of the gauge, and by application of a repetition pattern finds a coincident scale, that would indicated the value perforated. It is a slow and burdensome and not very well defined procedure especially when dealing with a certain range of scales, in such a way that perforations of the order of 11, 111/4, 111/2, 113/4, turn out to be very difficult to differentiate up to the extent that there are catalogues of stamps that only distinguish up to half of the perforation points. There are other measuring instruments such as the digital perforation gauge which is difficult to handle as requires a digitized image of the stamp; or the electronic perforation gauge, also based on photographic procedures, which is extremely expensive.